Citations

Abstract Epigenetic silencing of tumor suppressing genes by promoter-specific DNA methylation is common in many types of cancer. As an early event, this process has been well shown to promote tumor initiation and progression; however little is known how such epigenetic silencing can contribute to tumor metastasis. The PRKD1 gene encodes Protein Kinase D1 (PKD1), a serine/threonine kinase expressed in epithelial cells of the normal mammary gland that maintains the epithelial phenotype of normal breast cells and prevents epithelial-to-mesenchymal transition (EMT). PKD1 is also a critical suppressor of tumor cell invasion and is silenced in expression and activity during breast tumor progression. Here, we show that aberrant methylation of PRKD1 promoter region is not only correlated with the silencing of its expression but is also associated with invasiveness of breast cancer cell lines and with aggressiveness of breast tumors. Using the highly invasive MDA-MB-231 cells, we show that the inhibition of PRKD1 promoter methylation with the DNA methyltransferase inhibitor decitabine restores PKD1 expression and significantly decreases their invasive abilities in vitro. More importantly, in a tumor xenograft model it dramatically blocks tumor spread and metastasis to the lung in a PKD1-dependent fashion. Our data suggest that the status of epigenetic regulation of the PRKD1 promoter can provide valid information on the invasiveness of breast tumors, and therefore could serve as an early diagnostic marker. Moreover, targeted upregulation of PKD1 expression may be used as a therapeutic approach to reverse the invasive phenotype of breast cancer cells. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-05-24.

Abstract Background Trastuzumab (T) combined with chemotherapy improves survival of women with HER2-positive breast cancer. Dual therapy with T and other HER-2 targeted agents (lapatinib/pertuzumab) has demonstrated improved efficacy compared to T alone in advanced breast cancer, and is in clinical trials in early stage disease. We hypothesize that subgroups of patients with HER2-positive tumors and limited tumor burden (tumor size and no or few positive lymph nodes) have a favorable outcome and would not be candidates for dual therapy. This study will analyze the disease-free survival (DFS)and overall survival (OS) of patients with early stage breast cancer treated with chemotherapy and T in the seminal randomized studies (RCTs). Methods RCTs were identified by a Medline search from 2004-2013. Trial groups from five phase III RCTs agreed to provide data. TrialNumberEligibilityRegimenNSABP B312130T1-3; pN1, pN2a, or pN3a; M0ACx4 then Tx4 VSACx4 then THx4 then Hx40wkNCCTG N98313505T1-3; pN1-2; M0ACx4 then Tx12wk VS ACTx4 then Hx52wk VS ACx4 then Tx12wk then Hx40wkHERA5102T1-3; pN1-2; M0Any (neo)adjuvant regimen, then H q3wk x1yr VS H q3wk x 2yr VS observationFinHER232T1-4; N0-3; M0Vx3 or T*x3 then FECx3 VS Vx3 or T*x3 with Hx9wk then FECx3PACS043010(528 HER2+)T1-3; pN1-2; M0FE(100)Cx6 VSFE(100)Cx6 then Hx1yr VS T*E(75) x6 VS T*E(75) x6 then Hx1yrA, adriamycin; C, cyclophosphamide; T, paclitaxel; T*, docetaxel; H, trastuzumab; P, carboplatin; F, 5-fluorouracil; E, epirubicin; Treatment regimen also included 5 years of hormonal therapy for ER positive patients. The ER+/HER2+ and the ER-/HER2+ cohorts will be analyzed separately. Patients with tumors 3 cm or smaller (T1a, T1b, T1c and >2 cm- 3cm) and 0, 1, 2 and 3 positive lymph nodes will be included. Initially a log rank test will be used to determine if the survival results are different by study. If there is no difference across studies, Kaplan-Meier survival curves with confidence intervals will be estimated. If there is a difference between studies, individual Kaplan-Meier curves will be estimated and the mean of the curves will be estimated along with confidence intervals using the adjusted standard deviation. Estimates at 3, 5 and 8 years will be presented as well as estimates of the event rates within each subpopulation defined by tumor size, number of positive lymph nodes, and ER status. Survival endpoints of DFS, and OS as defined in the original studies will be analyzed. Results and Conclusion Data from the five trials will be analyzed and an abstract provided prior to the meeting. Subgroups of patients with a very favorable outcome when treated with adjuvant chemotherapy and T will be identified. Our survival estimates might serve as benchmarks for future trials evaluating therapy reduction. Our results will complement those of the Dana Farber single arm multicenter trial in patients with “low risk” HER2-positive disease (APT trial; NCT00542451), being submitted to SABCS 2013. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S6-03.

Abstract Background: Imaging biomarkers of cellular division offer promise as non-invasive measures of tumor response. 3’-deoxy-3’[18F]-fluorothymidine ([18F]-FLT) positron emission tomography (PET) imaging generally correlates with pathology-based measurements of cancer proliferation, especially the Ki67 score. Though clinical studies have associated changes in [18F]-FLT uptake with therapeutic response, clinical studies validating its ability to assess cell proliferation are comparatively lacking. The goal of this study was to determine quantitative relationships between [18F]-FLT compared with molecular and cellular metrics of proliferation during treatment for locally advanced breast cancer (LABC). Methods: Baseline [18F]−FLT-PET scans were obtained prior to the initiation of chemotherapy for LABC from patients enrolled at several academic oncology study sites. MRI scans, and transmission CT scans were obtained. Core needle biopsies were obtained to determine Ki-67 indices using immuno-histochemistry and to assess an mRNA signature based measurement of proliferation. Prospectively specified quantitative relationships between PET, Ki67 immunohistochemistry and the mRNA signature were evaluated using image-matched tumor specimens. Correlations between volumetric MRI changes and pathologic responses were evaluated in a post-hoc exploratory analysis. Results: Motivated by the hypothesis that effective chemotherapies should decrease tumor cell proliferation, FLT-PET was compared with biomarkers of proliferation including Ki67 and the mRNA signature during neoadjuvant treatment for LABC. [18F]-FLT correlated both with the Ki67 labeling index (SUVmean r = 0.53) and with the proliferation signature (SUVmean r = 0.7), validating the principle of thymidine analogue imaging. However, variability in the [18F]-FLT PET and tumor cell proliferation measures likely contributed to correlations less than pre-specified target values considered appropriate for clinical use (r > 0.78). Moreover, none of the proliferation biomarkers predicted pathologic complete responses at the end of neoadjuvant therapy ∼16 weeks after the 3 week response scan. In contrast, an evaluation of change in tumor volume measured by MRI after 3 weeks of therapy confirmed its superior ability to predict pCR and tumor re-staging. Conclusion: With large numbers of cancer drugs entering therapeutic pipelines, early efficacy measures remain critical for drug development. The 3-4 month neoadjuvant treatment paradigm for LABC offers unique opportunities for drug evaluation. Functional imaging using [18F]-FLT has been advanced as an assessor of cellular proliferation, potentially offering a non-invasive approach to response evaluation. While [18F]-FLT generally correlated with proliferation, its lack of association with patient responses likely limit its clinical utility. On the other hand, the predictive value of MRI offers unique opportunities for future trial designs and confirms previous reports (1). 1. N. M. Hylton et al., Locally advanced breast cancer: MR imaging for prediction of response to neoadjuvant chemotherapy. Radiology 263, 663 (2012). Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-11.

Abstract Background: The Phase III trial (NCT00337103) compared eribulin (E) with capecitabine (C) in patients (pts) with metastatic breast cancer (MBC) in the 1st-, 2nd-, and 3rd-line setting. Median overall survival (OS) was 15.9 and 14.5 months (HR 0.88; 95% CI 0.77, 1.00; P = 0.056) and median progression-free survival (PFS) was 4.1 and 4.2 months (HR 1.08; 95% CI 0.93, 1.25; P = 0.30) for E and C, respectively. This analysis compares toxicity and efficacy of E and C in relation to age. Material and methods: In this post-hoc exploratory analysis, the effect of age on the incidence of adverse events (AEs), OS, PFS, and objective response rate (ORR) with E and C were analyzed for two age groups: ≤65 years (E, n = 468; C, n = 491) and >65 years (E, n = 86; C, n = 57). For OS and PFS, analyses were stratified by HER2 and geographic region. Results: With increasing age, the proportion of pts with worse performance status (PS ≥1: 54.5% vs 69.2% for ≤65 and >65 years, respectively), ER+ (47.4% vs 57.3%), and PgR+ MBC (41.3% vs 45.5%) increased, and the proportion with triple-negative MBC decreased (26.6% vs 20.3%). With both treatments, AEs were reported in a higher proportion of pts in the older age group, this becoming more apparent for grade 3+ AEs (E: 64.6% vs 70.2%, and C: 45.0% vs 54.4% for ≤65 and >65 respectively). With E, there was a trend for increased incidence of grade 3/4 neutropenia (45.0% vs 50.0%) and leukopenia (13.7% vs 22.6%) but, in contrast, decreased peripheral sensory neuropathy (3.9% vs 1.2%) with increasing age. For C, there was a trend for increased palmar-plantar erythrodysethesia syndrome (total: 44.4% vs 50.9%; grade 3/4: 14.1% vs 17.5%), and grade 3/4 fatigue (1.8% vs 7.0%) and diarrhea (4.7% vs 10.5%) with increasing age; emesis and nausea were similar for both age groups. Dose adjustments due to AEs with E were slightly higher in the older age group: withdrawals 7.4% vs 10.7%; dose reductions 31.1% vs 36.9%; and dose delays 30.9% vs 36.9%. With C, there was a trend for an increased incidence of withdrawals (9.2% vs 21.1%) and dose delays (34.2% vs 49.1%) due to AEs with increasing age: the incidence of dose reductions was slightly higher in the older age group (31.3% vs 36.8%). In an unadjusted analysis, a trend for improved OS with E vs C was observed in both subgroups (≤65 years: median 15.8 vs 14.5 months; HR 0.90; 95% CI 0.78, 1.04; P = 0.16, and >65 years: median 18.4 vs 14.1 months; HR 0.74; 95% CI 0.50, 1.12; P = 0.16). PFS and ORR for E and C were: median PFS: E, 4.0 and 5.4 months; C, 4.2 and 5.9 months; ORR: E, 10.9% and 11.6%; C, 11.6% and 10.5%, in the ≤65 and >65 groups respectively. Conclusions: This exploratory and unadjusted analysis suggests a trend for improved OS with E in both younger and older pts with MBC. With both treatments there was a suggestion that AEs were reported in a higher proportion of pts in the older age group, this becoming more apparent for grade 3+ events. Specifically, these data suggest an increased incidence of grade 3/4 diarrhea, dose delays, and study withdrawal due to AEs in pts treated with C, and potentially suggest that with E there may be less difference between the AE profile in younger vs older pts than with C. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-13-04.

Abstract Background A Phase III trial (Study 301; NCT00337103) in MBC comparing eribulin (E) with capecitabine (C) showed a trend for improved overall survival (OS) (hazard ratio [HR] 0.88; 95% CI 0.77, 1.00; P = 0.056) but not progression-free survival (PFS) (HR 1.08; 95% CI 0.93, 1.25; P = 0.30) with E. In order to investigate this apparent discordance, post-hoc analyses assessed the effect of PPT and events defining disease progression on OS. Methods Pts with locally advanced or MBC who had received an anthracycline and a taxane (≤2 prior chemotherapy regimens for advanced disease), were randomized to E (554) or C (548). Co-primary endpoints were OS and PFS. The impact of PPT on OS was assessed by analysis of exploratory PPT subgroups. Analyses of OS sensitivity censoring at time of PPT, and OS adjusted by PPT as a time-dependent covariate in a Cox regression model, were performed. The relationship between OS and progression events (appearance of a “new” lesion or metastasis [NM]; increase in size of pre-existing lesions [IPEL]; or other [death, clinical progression, or censored]) was investigated using Cox regression. Results PPT was received by 70% and 62% of E and C pts, respectively. For E pts, there were no significant OS differences by PPT (Table 1). Excluding 56 pts (22 E, 34 C) who received anti-HER2 therapy as PPT from the intent-to-treat OS analysis, OS was longer with E (HR 0.86; 95% CI 0.76, 0.99; nominal P = 0.03). OS sensitivity analysis censoring at time of PPT was consistent with the overall study results (HR 0.82; 95% CI 0.65, 1.03). Assessment of the overall effect of PPT, adjusting by PPT as a time-dependent covariate in a Cox regression model, showed that OS was longer with E (HR 0.85; 95% CI 0.75, 0.97; nominal P = 0.02). Progression due to NM or IPEL occurred in 271 and 147 of E pts, and 285 and 129 of C pts, respectively. Median OS was similar between arms in pts with IPEL and longer with E vs C in pts with NM (Table 2). Pts who progressed due to NM were at higher risk of death (HR 2.12; 95% CI 1.84, 2.43; nominal P<0.01). Conclusions Treatment with C or any other PPT after progression on E did not account for the trend in OS benefit with E observed in the primary analysis. Pts who progressed with NM had a worse prognosis than those with IPEL. The appearance of NM was highly correlated with OS, and the apparent discordance between PFS and OS seems to be related to these different progression events. Tab 1: OS by PPT after EPPTAll ptsC as 1stOther than C as 1stC at any timeOther than C at any timeNoneN554221169275115164Median OS, months (95% CI)15.9 (15.2, 17.6)18.3 (15.8, 20.9)19.9 (17.6, 24.0)19.6 (17.6, 21.5)18.0 (15.4, 22.7)7.4 (6.2, 9.1) Tab 2: OS by progression event Progression event NMIPELOther ECECECN271285147129136134Median OS, months (95% CI)15.5 (14.2, 17.5)12.9 (11.3, 14.5)17.4 (14.4, 19.7)17.4 (15.3, 20.9)16.7 (14.8, 24.2)15.5 (11.7, 18.3)HR (95% CI)0.81 (0.68, 0.97)1.13 (0.87, 1.46)0.78 (0.59, 1.03)Nominal P -value0.020.350.08Time to NM or death, months (95% CI)5.8 (5.2, 6.5)5.2 (4.3, 5.9)NANAHR (95% CI)0.90 (0.77, 1.05)NANANominal P-value0.17NANA Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-13-03.

Abstract Background: Hsp90 is a molecular chaperone protein required for the stabilization and activation of many proteins, referred to as Hsp90 ‘clients’, such as HER2, HIF1-a, EGFR, ER, PI3K, AKT, P53 and VEGFR. The drug candidate, ganetespib is a novel triazolone inhibitor of Hsp90, with over 700 patients treated to date. Ganetespib has shown activity in preclinical models of HER2+, ER+/PR+ and TNBC. Early clinical trials documented ganetespib single agent activity in heavily pretreated HER2+ and TNBC patients. Ganetespib has been well tolerated in clinical trials with a favorable safety profile. This efficacy-screening study is designed to provide further evidence of ganetespib activity and identify potentially predictive biomarkers in metastatic breast cancer (BC). Methods: The ENCHANT-1 Trial is an international, first-line 2-cohort Phase 2 study in BC patients: Cohort A, HER2 amplified (n = 35), and Cohort B, TNBC (n = 35). Patients who present with previously untreated metastatic disease are eligible for treatment with ganetespib at 150 mg/m2 twice weekly on 3 out of 4 wks, for a total of up to 12 wks. Primary endpoint: ORR assessed using RECIST1.1 criteria. Key secondary endpoints include metabolic response as assessed by PET/CT at wk 3 utilizing modified EORTC criteria. Disease progression (PD) at wk 3 by PET imaging indicates discontinuation of study therapy, and is performed to quickly offer patients with metabolic PD a standard of care treatment. The study is designed as Simon 2-stage requiring at least one OR in 15 patients for the respective cohort to expand to 35 patients. A Steering Committee is established to oversee the overall study and review the interim results. Results: The study was initiated in 23 centers globally. At the time of submission, a total of 17 patients had been enrolled; TNBC (n = 15) and HER2 (n = 2). Here we report the interim analysis in the TNBC cohort. The median age was 54 years (range 30 -77) with ECOG PS 0 (n = 7/15). Most patients (n = 9) presented with de novo metastatic disease. 5 patients were not evaluable for PET assessment (3 had not yet reached wk 3 and 2 withdrawn before wk 3 for clinical progression), and 9 patients were not evaluable for objective response at wk 6 (3 withdrawn before or at wk 3 for clinical progression and 6 had not yet reached wk 6 evaluation). In the 10 patients with evaluable PET imaging, 9 patients achieved metabolic (m) response (2 mPR, 4 mSD with dominant tumor shrinkage and 3 SD) and one patient with mPD. In the 6 patients evaluable for OR at wk 6, one patient achieved PR, 2 SD and 3 PD. Treatment with ganetespib was well tolerated; the most common AEs were mild or moderate diarrhea (8/15, 53%), fatigue (5/15, 33%), decreased appetite (4/15, 27%), insomnia (4/15, 27%), and nausea (4/15, 27%). Conclusion: Ganetespib single agent was generally well tolerated and showed anti-tumor activity TNBC patients as early as 3 weeks following treatment. PET seems to be a good tool to screen antitumor activity of new agents in early settings rather that in heavily pretreated patients. The TNBC cohort has met the protocol criteria for proceeding to stage 2. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-23.

Abstract Background: HER2 overexpression or amplification, occuring in ∼15-20% of breast cancers (BC), is associated with a poor prognosis. Trastuzumab (T) and pertuzumab (P) are humanized monoclonal antibodies that bind to different HER2 epitopes, inhibiting HER2 signaling. It was previously shown that first-line (1L) treatment of patients (pts) with HER2-positive metastatic breast cancer (MBC) with vinorelbine (V)+T had similar efficacy to docetaxel+T, but with fewer adverse events (AEs) (HERNATA). In a recent study, P+T+docetaxel significantly improved progression-free survival (PFS) and overall survival (OS) compared with T+docetaxel in pts with HER2-positive 1L MBC (CLEOPATRA). The objective of the VELVET study is to investigate the efficacy and safety of P+T+V for 1L treatment of HER2-positive MBC. Methods: This is a multicenter, open-label, single-arm, two-cohort, Phase II study. The recruitment target is 105 pts per cohort. Pts in Cohort 1 receive P+T+V as separate infusions. Pts in Cohort 2 receive P+T from a single infusion bag followed by V. The initial dose of P is 840 mg, followed by 420 mg q3w; the initial dose of T is 8 mg/kg, followed by 6 mg/kg q3w; V is administered at 25 mg/m2 in Cycle 1, followed by 30-35 mg/m2, on Days 1 and 8 of each cycle, q3w. Pts must have HER2-positive MBC or locally advanced BC (LABC) and a baseline left ventricular ejection fraction (LVEF) of ≥55%. Previous treatment with systemic nonhormonal anticancer therapy in the metastatic setting is not allowed. The primary endpoint is independently assessed overall response rate. Secondary endpoints include PFS, OS, and safety. Results: Interim safety data are presented for Cohort 1; 106 pts were enrolled. Median age at screening was 56 years. Median interval between initial BC diagnosis and enrollment was 2.6 years. 33% of pts had Stage IV BC at initial BC diagnosis. At diagnosis of advanced disease, 13% and 87% of pts had LABC and MBC, respectively. 54% of pts had previously received chemotherapy, including taxane (38%) and anthracycline (36%). 41% had prior T exposure. A median of 6 cycles of P, T, and V was received at the time of this analysis. An AE overview is shown in the table. Pts, n(%)N = 106Any AE102(96)Grade 338(36)Grade 417(16)Grade 52(2)aAny serious AE25(24)Most frequent (≥4 pts) grade ≥3 AEs Neutropeniab21(20)Febrile neutropenia6(6)Leukopenia5(5)Asthenia4(4)Constipation4(4)Diarrhea4(4)a Myocardial infarction and septic shock; b Covers ‘neutropenia’ and ‘neutrophil count decreased’ Grade ≥3 neutropenia/febrile neutropenia was experienced by 8% of pts in Cycle 1 and by 14% of pts in Cycle 2; this proportion decreased during subsequent cycles. There was no overall decrease in mean LVEF from baseline. Conclusions: The combination of P+T+V was well tolerated; no new safety signals were observed. The incidences of grade ≥3 neutropenia, febrile neutropenia, and leukopenia were lower than those previously observed in pts with HER2-positive MBC treated with 1L P+T+docetaxel in CLEOPATRA or those treated with T+V in HERNATA; however, it should be noted that the treatment period in these two studies was longer. Efficacy data for Cohorts 1 and 2 will be reported at the end of the study. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-10.

Abstract Background: Epidermal Growth Factor Receptor (EGFR, HER1) is known to heterodimerize with HER2 and may modulate the effectiveness of trastuzumab or lapatinib. Historically, it has been difficult to measure, but recently we reported a new, standardized, quantitative immunofluorescence assay and a novel EGFR antibody which showed that high levels of EGFR were associated with decreased benefit in the concurrent arm of the North Central Cancer Treatment Group (NCCTG/Alliance) N9831 trial (Rimm et al, SABCS 2012). Here we assess its value in the neo-adjuvant setting in the NeoALTTO trial. Methods: NeoALTTO randomized 455 breast cancer patients to neoadjuvant trastuzumab, lapatinib or both and showed benefit in both single anti-HER2 therapy arms, and the combination therapy showing about twice as much benefit as either single drug arm. We used the previously described AQUA method of quantitative immunofluorescence to measure EGFR levels using the D38B1 antibody on between 4 and 140 fields of view per slide on 353 specimens. The averaged EGFR score was standardized to the absolute concentration using cell lines and western blots and the 13 ng/ug total protein established in the N9831 trial was tested to determine predictive value for pathological complete response (pCR) defined as ypT0/is. Results: In NeoALTTO, 19% of the patients had EGFR levels above 13 ng/ug, compared to 16% in NCCTG N9831. The pCR rate was 35.3% in the patients with low EGFR, compared with 29.8% for high EGFR but this difference was not statistically significant. However, when adjusted for treatment and hormone receptor (HR) status, high EGFR is statistically significantly associated with lower response rate(p = 0.038). Continuous analysis measures were not significant. The effect on overall response at 6 weeks was also weakly significant when adjusting for treatment and HR status (p = 0.06). Surprisingly, for HR negative patients in the lapatinib only arm, the pCR rate in the low EGFR group was 47.2% compared with 16.0% in the high group. While this difference is statistically significant (p = 0.014), it should be interpreted cautiously because of the small numbers of patients and the multiple tests performed. Conclusions: High expression of EGFR by the AQUA platform appears to be associated with decreased pCR rate from HER2 targeted therapy in the neoadjuvant setting. This observation is consistent with NCCTG N9831. Although underpowered, high EGFR levels predicted decreased pCR rate from lapatinib, the opposite of that anticipated for this small molecule dual EGFR/HER2 inhibitor. Further studies are required to determine the clinical utility of this assay and the biological mechanisms underlying these observations. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-09.

Abstract Background: In 2000, cyclophosphamide(C), epirubicin(E) and fluorouracil (F) (CEF) and doxorubicin (A) and C followed by paclitaxel (T) (AC/T) given every three weeks were commonly used regimens in Canada and the USA to treat women with node positive or high risk node negative operable breast cancer. In a previous trial in women with locally advanced breast cancer, 3 months of dose-dense EC was equivalent to six months of CEF. We hypothesized that the addition of 3 months of a taxane following dose-dense EC would be superior to CEF alone or AC/T. In a randomized trial in women with early breast cancer we compared CEF, dose dense EC/T and AC/T. An interim analysis (JCO, 2010) conducted when 50% of the events for the relapse-free-survival (RFS) analysis were observed, demonstrated that AC/T administered every 3 weeks was significantly inferior to CEF or EC/T. The results of the final RFS including CEF versus EC/T will be presented. Methods: Women, 60 years or younger, with operable axillary node positive or high risk node negative breast cancer were randomized to adjuvant CEF, EC/T or AC/T. CEF was given for 6 cycles and consisted of: C 75 mg/m2 orally on Days 1–14, and E 60 mg/m2 and F 500 mg/m2, IV on Days 1 and 8. CEF patients received concurrent antibiotic prophylaxis. EC/T consisted of 6 cycles of EC every 14 days; E 120 mg/m2 and C 830 mg/m2, both IV on Day 1 with filgrastim 5 [ug]/kg/day subcutaneous from Days 2–13 and epoetin alpha 40,000 units subcutaneous once weekly. After completion of EC, 4 cycles of T 175 mg/m2 every 21 days with filgrastim and epoetin alpha were given. The AC/T regimen consisted of A 60 mg/m2 and C 600 mg/m2 IV every 21 days for 4 cycles. This was followed by T 175 mg/m2 every 21 days for 4 cycles. The final analysis for RFS was planned when 453 events were observed permitting the detection of a hazard ratio (HR) of 1.43 between CEF and AC/T and a HR of 1.43 between EC/T and the best of the other two arms. Quality of Life data using the EORTC C-30 and the Breast Cancer Chemotherapy questionnaires were collected throughout the study. The results will be available at the time of the presentation. Results: A total of 2104 women were enrolled between December 2000 and April 2005. The required 453 events for the RFS analysis were observed by the clinical cut-off date of March 30, 2012. At this point 369 deaths had been observed. The median follow-up is 87.5 months. Outstanding data and queries are currently being collected and reviewed with an expected database lock and final analysis mid August, 2012. Febrile neutropenia remains higher on the CEF and EC/T arms while more neuropathy was seen in the taxane containing regimens. Conclusions: Although the two regimens considered a standard of care at the time the study was initiated are no longer widely used, the trial results will enhance our understanding of the magnitude of benefit of taxane following an anthracycline, the significance of cumulative anthracycline dose, and the role of dose density/ intensity as backbone of conventional chemo regimens. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-13-01.

Background—Nuclear reprogramming inculcates pluripotent capacity by which de novo tissue differentiation is enabled. Yet, introduction of ectopic reprogramming factors may desynchronize natural developmental schedules. This study aims to evaluate the effect of imposed transgene load on the cardiogenic competency of induced pluripotent stem (iPS) cells.Methods and Results—Targeted inclusion and exclusion of reprogramming transgenes (c-MYC,KLF4,OCT4, andSOX2) was achieved using a drug-inducible and removable cassette according to the piggyBac transposon/transposase system. Pulsed transgene overexpression, before iPS cell differentiation, hindered cardiogenic outcomes. Delayed in counterparts with maintained integrated transgenes, transgene removal enabled proficient differentiation of iPS cells into functional cardiac tissue. Transgene-free iPS cells generated reproducible beating activity with robust expression of cardiac α-actinin, connexin 43, myosin light chain 2a, α/β-myosin heavy chain, and troponin I. Although operational excitation–contraction coupling was demonstrable in the presence or absence of transgenes, factor-free derivatives exhibited an expedited maturing phenotype with canonical responsiveness to adrenergic stimulation.Conclusions—A disproportionate stemness load, caused by integrated transgenes, affects the cardiogenic competency of iPS cells. Offload of transgenes in engineered iPS cells ensures integrity of cardiac developmental programs, underscoring the value of nonintegrative nuclear reprogramming for derivation of competent cardiogenic regenerative biologics.